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Hypothetical scenarios

Entirely environmental:
MZ 0% - 100% and not expected to be different from DZ
DZ 0% - 100% and not expected to be different from MZ

Complex - environmental trigger coupled with recessive genetic susceptibility
MZ higher than for DZ most but not all the time (because of the 0% above)
DZ lower than for MZ most but not all the time (because of the 0% above)

Now I am likely off on some of these numbers but it seems to me the power of these MZ/DZ twin studies is over-estimated and is only useful in a minority of situations. Only two of the above scenarios would be illuminated by twins studies. (None by self-reported twins studies.) And we don't know for sure which those are because we don't know what causes scoliosis.

Last edited by Pooka1; 05-08-2009 at 06:36 AM.

Sharon, mother of identical twin girls with scoliosis

No island of sanity.

Question: What do you call alternative medicine that works?Answer: Medicine

Some good ways to initally vet twin study results

1. See if the ratio of MZ to DZ twins is in line with what we know about the general population.

Until recently when IVF and such became more prevalent, the incidence of DZ and MZ was known and known to be fairly steady. IIRC, it was about 2/3 DZ and 1/3 MZ (I should check that). The Danish twins study should be vetted to see if that ratio is close to what it should be. Of course now this ratio is all over the place and likely not steady.

2. Check that the incidence of scoliosis is about the same as in the general population. In the case of the Danish study, it is LOW by half to two-thirds. That signals a problem of under-reporting scoliosis in the study population. Because even MZ twins can differ greatly in their curves, this would seem to compromise the results per se.

Sharon, mother of identical twin girls with scoliosis

No island of sanity.

Question: What do you call alternative medicine that works?Answer: Medicine

High blood pressure and CMV infection

FRIDAY, May 15 (HealthDay News) -- A hidden viral infection that most adults harbor could be a cause of high blood pressure, animal studies indicate.

Mice infected with cytomegalovirus (CMV) were more likely to develop not only high blood pressure but also the hardening of the arteries called atherosclerosis, according to a report in the May 15 issue of PLoS Pathogens by researchers at Beth Israel Deaconess Hospital in Boston.

"This could be of immense importance," said lead researcher Dr. Clyde Crumpacker, a professor of medicine at Harvard Medical School and an investigator in the Division of Infectious Diseases at Beth Israel Deaconess. "The implication for the human population is that antiviral therapy or a vaccine could be an intervention for high blood pressure."

Blood vessel problems related to CMV infection were first noted in heart transplant recipients, Crumpacker said. Those who were CMV-positive were more likely to have blockage of the heart arteries.

"We were able to measure blood pressure directly in the arteries of the mice," Crumpacker said. The studies showed increased blood pressure in the infected mice after six weeks, but not in the uninfected group. It also showed that 30 percent of the infected mice in the high-cholesterol group developed atherosclerosis as well as high blood pressure.

Transmission of HCMV occurs from person to person through bodily fluids. Infection requires close, intimate contact with a person excreting the virus in their saliva, urine, or other bodily fluids. CMV can be sexually transmitted and can also be transmitted via breast milk, transplanted organs, and rarely from blood transfusions.

Although HCMV is not highly contagious, it has been shown to spread in households and among young children in day care centers. Transmission of the virus is often preventable because it is most often transmitted through infected bodily fluids that come in contact with hands and then are absorbed through the nose or mouth of a susceptible person. Therefore, care should be taken when handling children and items like diapers. Simple hand washing with soap and water is effective in removing the virus from the hands.

Just because a disease hits a family particularly hard doesn't mean it's genetic. There are usually better explanations including infectious disease.

I just love your research into possibly infectious disease causing at least some of the scoliosis cases out there. I hope to God you are right and that a large portion of these cases and other diseases could just be vaccinated out of existence. Time will tell. Keep up your research. It's fascinating. I'm sending best wishes to you and your son.

Thanks!

Thanks for your thoughts. My son goes in on Monday at 3:30pm and I'm crossing my fingers that his progression wasn't too bad.

We started strength training, stretching and balance training a week ago. I wish we had started 8 months ago when he was diagnosed but we didn't know what to do.

I hope to God you are right and that a large portion of these cases and other diseases could just be vaccinated out of existence. Time will tell.

I know how crazy it sounds that a back disorder could be caused by an infection but in my opinion it's almost certainly the environmental component behind most cases of progressive AIS. I'll keep watching the headlines.

Yep

Interesting, Vical Incorporated (VICL) has a vaccine for cmv in clinical trials now.

I'm not sure about the release date on this particular CMV vaccine but I know that scientists have been working on a variety of these for a long time. It's my understanding that inside of a decade children and perhaps adults will be vaccinated against CMV.

Adolescent Idiopathic Scoliosis (AIS) is Scoliosis of unknown cause. In the animal studies that I listed the cause is known to be an infection. Whether the two are similar in some way is unknown.

Yes but in the identical way that they determined the cause in these other animal models, don't you think they did the same thing with humans and they ruled that out for AIS long, long ago? These guys are very clever as a rule.

I mean if you have a non-human animal model and you had the wherewithal to find the cause of the scoliosis there, why couldn't they do it with humans?

That's why they say AIS only occurs in humans. It means they have ruled out all known causes of scoliosis in any animal and they haven't yet identified the cause in humans. At this point, AIS is unique to humans in the animal kingdom.

Sharon, mother of identical twin girls with scoliosis

No island of sanity.

Question: What do you call alternative medicine that works?Answer: Medicine

Yes but in the identical way that they determined the cause in these other animal models, don't you think they did the same thing with humans and they ruled that out for AIS long, long ago?
I mean if you have a non-human animal model and you had the wherewithal to find the cause of the scoliosis there, why couldn't they do it with humans?

Because of ethical concerns, you cannot cause scoliosis in a human. You can only observe it and try to sort out the causes. In animal models, you design an experiment where you change one thing and observe the outcome. Give the animal CMV, mutate a gene, introduce a drug, change diet etc. and then see what happens. Its not at all the same.

My disclaimer to this statement, is that I have no idea if this is what was done in the animals that were cited. I didn't read the details.

Because of ethical concerns, you cannot cause scoliosis in a human. You can only observe it and try to sort out the causes. In animal models, you design an experiment where you change one thing and observe the outcome. Give the animal CMV, mutate a gene, introduce a drug, change diet etc. and then see what happens. Its not at all the same.

My disclaimer to this statement, is that I have no idea if this is what was done in the animals that were cited. I didn't read the details.

I didn't read the papers either. I assumed it was where researchers tracked down the cause of naturally occurring scoliosis in other animal models. If it is where researchers INDUCE scoliosis in animals that wouldn't normally have soliosis then the research is even less relevant than I thought as they are by definition NOT inducing idiopathic scoliosis.

I must admit that possibly didn't even occur to me because then I don't know why Dingo would cite it. It would be completely irrelevant to AIS.

Sharon, mother of identical twin girls with scoliosis

No island of sanity.

Question: What do you call alternative medicine that works?Answer: Medicine